Refractive index tomograms and dynamic membrane fluctuations of red blood cells from patients with diabetes mellitus

Abstract

In this paper, we present the optical characterisations of diabetic red blood cells (RBCs) in a non-invasive manner employing three-dimensional (3-D) quantitative phase imaging. By measuring 3-D refractive index tomograms and 2-D time-series phase images, the morphological (volume, surface area and sphericity), biochemical (haemoglobin concentration and content) and mechanical (membrane fluctuation) parameters were quantitatively retrieved at the individual cell level. With simultaneous measurements of individual cell properties, systematic correlative analyses on retrieved RBC parameters were also performed. Our measurements show there exist no statistically significant alterations in morphological and biochemical parameters of diabetic RBCs, compared to those of healthy (non-diabetic) RBCs. In contrast, membrane deformability of diabetic RBCs is significantly lower than that of healthy, non-diabetic RBCs. Interestingly, non-diabetic RBCs exhibit strong correlations between the elevated glycated haemoglobin in RBC cytoplasm and decreased cell deformability, whereas diabetic RBCs do not show correlations. Our observations strongly support the idea that slow and irreversible glycation of haemoglobin and membrane proteins of RBCs by hyperglycaemia significantly compromises RBC deformability in diabetic patients.

Synergistic Integration of Laboratory and Numerical Approaches in Studies of the Biomechanics of Diseased Red Blood Cells

“…As shown in the AFM images in Figure 9 a (left), a deeper dimple region is present in healthy RBCs, while a shallow dimple or no dimple occurs in diabetic RBCs. Similar results were presented by Lee et al [ 151 ] via common-path diffraction optical tomography (cDOT). The 2D membrane height maps of RBCs from healthy controls and from diabetic patients in Figure 9 a (right) imply a loss of the center dimple region for their representative diabetic RBCs.…”

“…The stretched states of N-RBC and D-RBC2 under an external tensile force of 100 pN are also presented in Figure 9 c. It is obvious to see the reduced cell stretching response of D-RBC2 against N-RBC at the same tensile force. Chang et al [ 152 ] also found a diminished membrane fluctuation reflected in the narrower fluctuation distribution in Figure 9 d of the T2DM RBCs compared to the normal RBCs, which is qualitatively consistent with experimental work ( Figure 9 c) by Lee et al [ 151 ]. As for T2DM RBCs with the abnormal near-oblate shape (D-RBC2 and D-RBC3), much narrower fluctuation distributions are presented (see Figure 9 c).…”

“…The 2D membrane height maps of RBCs from healthy controls and from diabetic patients in Figure 9 a (right) imply a loss of the center dimple region for their representative diabetic RBCs. Lee et al [ 151 ] also estimated the mean membrane fluctuation by spatially averaging the 2D membrane fluctuation map of individual RBCs (see Figure 9 b). They found a significant decrease in the mean membrane fluctuation of diabetic RBCs compared to healthy RBCs, which indicates an impaired deformability of diabetic RBCs.…”

Morphometric analysis of erythrocytes from patients with thalassemia using tomographic diffractive microscopy

“…Second, the flicking of the RBC membrane at the time scale of 2 s is related to biophysical properties of the membrane 37 and has been quantified with QPI to range from 49 to 60 nm. 16 Considering the thickness of healthy RBCs being about 2 μm, the flicking causes less than 3% fluctuations in the volume. Therefore, it was ignored in this study.…”

“…10 The physical thickness and three-dimensional (3-D) RI maps of RBCs can be reconstructed from multiple 2-D phase images acquired at various illumination directions using diffraction tomography techniques. 14 Recently, studies have characterized 3-D morphological indices of RBCs including the surface area, volume, and sphericity and have demonstrated significant differences between RBCs from the cord blood of newborn infants and that of maternal or nonpregnant women 15 and between normal RBCs and RBCs from patients with diabetes mellitus, 16 malaria, 14 iron-deficiency anemia, 17 reticulocytes, 17 hereditary spherocytosis, 17 and sickle-cell disease. 11,[17][18][19] These 3-D RBC parameters provide additional morphometrics for hematologists to better distinguish and understand blood diseases related to deformation of RBCs.…”